Method of making piston pins



Aug. 4, 1936. Q ABBE 2,049,411

METHOD OF MAKING PISTON PINS Filed March 19, 1955 Patented Aug. 4, 1936 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to piston pins such as are used in internal combustion engines, and relates more particularly to an improved method of making such pins.

It is the general object of my invention to provide a new and improved method of making a piston pin, by which method a piston pin of light and uniform weight, increased strength and exceptional utility may be economically produced.

My invention further relates to certain ordered procedure which will be hereinafter described and. more particularly pointed out in the appended claims.

A preferred manner of practicing my invention is shown in the drawing, in which Figs. 1, 2, and 3 are sectional elevations showing successive steps in the production of a cupshaped blank used in carrying out my invention;

Fig. 4 is an end View, looking in the direction of the arrow 4 in Fig. 3;

Fig. 5 is a side elevation showing a further step in my improved method, and

Fig. 6 is a sectional side elevation of the finished piston pin.

It is desirable in the production of piston pins for use in high speed internal combustion engines that the pins shall be of light and uniform weight, that they shall be reenforced and strengthened in their middle portion, and that they shall be provided with a circumferential oil groove at said middle portion. Such a piston pin is shown in section in Fig. 6.

In carrying out my improved method, I first take a circular blank of sheet steel of suitable composition, and subject it to a press operation by which it is drawn into the cup-shaped blank A shown in Fig. 1.

I then subject the blank A to one or more pressing or drawing operations until the blank assumes the form indicated at B in Fig. 2. It will be noted that the blank B is much elongated in comparison to the blank A, and that the recess I0 within the blank is given a substantial outward taper, while the walls ll become correspondingly thinner toward the open end of the blank.

I then submit the blank B to an additional press and punching operation by which it is transformed to the blank C shown in Figs. 3 and 4.

'This blank C preferably has an outwardly projecting annular rib [2 on its end face and is provided with an axial opening l3 in the depressed portion l4 within the rib 12.

Having prepared two blanks C as above described, I assemble the blanks end to end as shown in Fig. 5, and then submit the blanks to a welding operation while under axial pressure,

so that the blanks C are securely welded together at their adjacent ends, and said adjacent ends form a unitary partition in the middle portion 5 of the piston pin as indicated at IS in Fig. 6. During this welding operation, the blanks C are firmly held with their recesses I0 accurately aligned axially.

After the two blanks are thus permanently and 10 securely welded together at their adjacent faces, the piston pin may be finished by any suitable cutting or grinding operations. The outer surface of the pin may then be given a finished grinding, and the oil groove 20 may be ground 5 at the middle portion.

It will be noted by reference to Fig. 6 that the oil groove 29 is provided at the particular point in the piston pin which is firmly reenforced by the partition 15, so that the pin is not weakened 20 by the provision of the oil groove, as has been the case in pins previously used and formed of straight tubular material without internal reenforcement. w

It will also be noted that the groove 20 comes 25 at that part of the pin where the rounded corners 22 (Fig. 5) of the blanks C are located. Consequently, it is not necessary for these corners to be entirely flattened out in the welding operation, as any slight depression left between the 30 corners will be removed in grinding the oil groove 20.

The provision of the axial holes 13 provides a vent during the welding operation and prevents the formation of air-pockets between the welded portions. The holes [3 also permit cross flow of lubricant when the pin is in use.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the exact procedure herein disclosed, otherwise than as set forth in the claims, but what I claim is:-

1. The method of making an axially elongated piston pin which comprises forming a pair of deep cup-shaped blanks by a series of successive drawing operations, assembling said blanks with their closed ends abutting, holding said blanks in axial alignment, Welding said blanks together at their abutting ends to form a piston pin with a reenforcing partition at its middle portion, and thereafter finishing the external surface of said piston pin.

2. The method of making an axially elongated piston pin which comprises forming a pair of deep cup-shaped blanks by a series of successive drawing operations and flattening the closed ends of said blanks and decreasing the thickness of the side wall of each blank toward the open end of said blank, assembling said blanks with their closed ends abutting, holding said blanks in axial alignment, welding said blanks together at their abutting ends to form a piston pin with a reenforcing partition at its middle portion, and thereafter finishing the external surface of said piston pin concentric with the internal surfaces of said blanks.

3. The method of making a piston pin which comprises forming a pair of cup-shaped blanks, assembling said blanks with their closed ends abutting, holding said blanks in axial alignment, welding said blanks together at their abutting ends to form a piston pin with a reeni'orcing partition at its middle portion, thereafter finishing the external surface of said piston pin, and forming a circumferential oil groove at the middle reenforced portion of said pin.

EARL C. ABBE. 

